Towing With a Continuously Variable Transmission

Peculiarities of Towing a CVT-Equipped Car

Car manufacturers are constantly improving components and systems integrated in new models. Thanks to new technologies, conventional manual transmissions are gradually forced out from the automotive market by more sophisticated and automatically shifting transmissions, such as continuously variable transmissions (CVTs).

Such transmission solutions are notable not only for design peculiarities and operating principles, but also entail specific rules of operation and some restrictions, which are commonly specified in manuals provided by carmakers. For instance, sometimes it happens that your car can get stuck in the middle and the only way out is to tow it to the nearest repair shop. It can become a real problem for owners of CVT-equipped cars, as not all drivers know how to do it accurately without any harm to a pricy transmission unit. In this article, we will consider the main peculiarities of CVT transmissions and how to tow a CVT-equipped car properly.

Technical peculiarities of CVT transmissions

Nowadays, many automotive brands such as Toyota, Mitsubishi, Subaru, Honda, Nissan are notable for extensive use of CVT s and popularity of this transmission type is caused by a number of reasons.

First of all, design peculiarities of this transmission type ensure gradual and smooth change of gear ratios. In other words, there are no fixed steps (gears) compared to other types of transmission. This special feature guarantees faster accelerations and smooth driving, as there are no power losses during torque transmission from the engine to the drive wheels. Moreover, there are no kicks or jerks when shifting gears.

The popularity of this type of transmission is also motivated by the low cost of manufacture compared to other types of automatic transmissions. However, the main drawback of this transmission lies in relatively small operational resource, especially if CVTs are paired with powerful engines. Due to its design peculiarities, CVTs are unable to operate under high loads. Thus, CVTs are usually coupled with low-power engines.

The main parts of CVT transmissions:

• Shafts ( input and output);
• Pulleys;
• CVT belt/chain;
• Valve body (regulates the supply of oil pressure to the pulleys);
• CVT pump ( regulates the pulleys operation);
• Planetary gear (for reverse driving);
• Oil pump, filter, cooling system.

General rules and recommendations on operation and maintenance of CVT transmissions are similar to conventional automatics, but there are also significant differences. In practice, CVTs require more frequent maintenance (oil and filter changes). If for conventional automatics it is necessary to change fluid every 50-60 thousand kilometers, for CVTs this procedure must be performed every 30-40 thousand kilometers. In fact, it is very important to prevent premature wear of the CVT unit. Oil starvation and inadequate fluid levels can lead to rapid wear of the pulley or belt.

In practice, it is necessary to avoid sudden accelerations and slowdowns. With sudden accelerations or extreme braking, some tears can occur on surfaces of the pulleys, resulting in the unit malfunction. It is also important not to allow overheating of the CVT unit. If necessary, additional cooling systems should be installed to prevent serious issues. Drivers also have to keep an eye on the condition of different types of sensors (such as speed, pressure or ABS sensors), as failures of these components can have a negative impact on the CVT operation.

Taking into account the abovementioned peculiarities, let us now proceed to the rules of towing a CVT-equipped car.

How to tow a CVT-equipped car

First of all, it is necessary to remember that in case of non-compliance with certain rules, a CVT transmission can be exposed to serious damages during the towing procedure. Ideally, it is desirable to entirely exclude the towing option and call a tow truck for safe transportation of the vehicle to the nearest repair shop.

If you can neither call a tow car nor continue driving, then it is required to understand and to follow specific towing rules. The main rules for towing a CVT-equipped car are the following:

• The engine of the car being towed must be started;
• Before starting towing, the gear lever must be shifted to N position;
• During towing, the vehicle speed should not exceed 50 km/h;
• The towing distance should be as short as possible and not exceed 50 km;

Failure to comply with the abovementioned rules can lead to serious damage of the transmission unit during towing. For example, if a CVT-equipped car is towed with a stalled engine, the CVT oil pump won't work. When the transmission fluid does not reach important transmission elements, the entire CVT unit will go into abnormal mode. As a result, there may be the following issues: overheating of the input shaft, damage plastic bearings and planetary gear, and failure of the secondary (output shaft). Most operating manuals for CVT-equipped cars include specific instructions on transportation/towing of the vehicles in case of any mechanical damages. Frequently, it is required to ensure a rigid towline between two cars, as the use of flexible ropes can be unacceptable.

There are 3 transportation/towing options:

• All wheels stand on a horizontal platform of the tow truck;
• A pair of wheels is rigidly attached to the tow truck;
• Towing with the help of fastening ropes.

It should be noted that it is possible to tow a trailer behind a CVT-equipped car if the weight of the trailer is within the car's towing capacity. The only case when you should not use a CVT-equipped car for towing is when it is stated the vehicle Owner's Manual.

Summary

When dealing with CVTs it is important to remember not only about its advantages (such as enhanced fuel economy, high efficiency, smooth operation) but also about more stringent requirements when it comes to maintenance and compliance with operating rules. If for some technical reasons, a CVT-equipped car gets out of order in the middle of the road, it is better to call a tow truck. If it is not possible, the towing procedure should be performed in accordance with the rules specified in the manual. When towing a CVT-equipped car, it is advised to strictly follow so-called "50x50" rule (the broken car should not be towed for more than 50 km with the speed higher than 50 km/h). Following all the recommendations listed above, it is possible to extend the service life of the transmission unit and other car systems.

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Source: https://go4trans.com/technical-transmission-general-articles/peculiarities-of-towing-a-cvt-equipped-car/

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